Currys currently have the Devolo Wireless Extender & WLAN twinpack (Devolo 1215) for £39.97 plus p&p. Nectar points are also available available if you are a collector.
Next nearest price for this set is around the £100 mark. They also have the Devolo 1145 Homeplug duo Powerline twin pack (only 14mps though) for £19.97.
Brand & Model No. - Devolo 1215
Product Type - HomePlug Wireless Extender
Connection - Extension using your electrics
Ideal usage - Extend the network everywhere
Installation - No extra drilling or cabling
Range - Up to 85Mbps Plug, 54Mbps Wireless
Range - Ranges up to 200m
Warranty - 3 year manufacturer warranty
Feature - Safe & Secure Hardware encryption
Power Saving - Power saving mode up to 30%